<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
<!-- <div id="dv1">111111</div>
<div id="dv2">222222</div> -->
<div id="box">
    我是DIV
    <p>11111</p>
    <p>22222</p>
</div>
<script src="js/jquery-3.6.0.min.js"></script>
<script>
$(function(){
    //$('#dv1').add('#dv2').css('background','red');
    //$('#box').find("p").addBack().css("fontSize","50px");
    //$('#box').contents().css("fontSize","50px");
    //console.log($("#box").contents().length)；
    //$('#box').find("p").end().css("fontSize","50px");
})
</script>
</body>
</html>